[fix] Updated device change_form template

Previously, the device change_form.html template extended
"config/device/change_form.html". However, after merging the device
deactivation feature, the inheritance order was modified.
As a result, enabling the Radius integration caused the
"Status" and "Charts" tabs to disappear from the device page.

openwisp_radius/integrations/monitoring/templates/admin/config/radius-monitoring/device/change_form.html

@@ -1,4 +1,4 @@
-{% extends "admin/config/device/change_form.html" %}
+{% extends "admin/monitoring/device/change_form.html" %}
 {% load i18n %}
 
 {% block inline_field_sets %}